/*
 * connection.h
 *
 *  Created on: Sep 23, 2017
 *      Author: root
 */

#ifndef CONNECTION_H_
#define CONNECTION_H_

extern int disable_anti_replay;

#include "connection.h"
#include "common.h"
#include "log.h"
#include "network.h"
#include "misc.h"

const int disable_conv_clear=0;//a udp connection in the multiplexer is called conversation in this program,conv for short.

struct anti_replay_t  //its for anti replay attack,similar to openvpn/ipsec 's anti replay window
{
	u64_t max_packet_received;
	char window[anti_replay_window_size];
	anti_replay_seq_t anti_replay_seq;
	anti_replay_seq_t get_new_seq_for_send();
	anti_replay_t();
	void re_init();

	int is_vaild(u64_t seq);
};//anti_replay;

void server_clear_function(u64_t u64);

#include <type_traits>

template  <class T>
struct conv_manager_t  // manage the udp connections
{
	//typedef hash_map map;
	unordered_map<T,u32_t> data_to_conv;  //conv and u64 are both supposed to be uniq
	unordered_map<u32_t,T> conv_to_data;

	lru_collector_t<u32_t> lru;
	//unordered_map<u32_t,u64_t> conv_last_active_time;

	//unordered_map<u32_t,u64_t>::iterator clear_it;

	void (*additional_clear_function)(T data) =0;

	long long last_clear_time;

	conv_manager_t()
		{
			//clear_it=conv_last_active_time.begin();
			long long last_clear_time=0;
			additional_clear_function=0;
		}
	~conv_manager_t()
		{
			clear();
		}
		int get_size()
		{
			return conv_to_data.size();
		}
		void reserve()
		{
			data_to_conv.reserve(10007);
			conv_to_data.reserve(10007);
			//conv_last_active_time.reserve(10007);

			lru.mp.reserve(10007);
		}
		void clear()
		{
			if(disable_conv_clear) return ;

			if(additional_clear_function!=0)
			{
				for(auto it=conv_to_data.begin();it!=conv_to_data.end();it++)
				{
					//int fd=int((it->second<<32u)>>32u);
					additional_clear_function(  it->second);
				}
			}
			data_to_conv.clear();
			conv_to_data.clear();

			lru.clear();
			//conv_last_active_time.clear();

			//clear_it=conv_last_active_time.begin();

		}
		u32_t get_new_conv()
		{
			u32_t conv=get_true_random_number_nz();
			while(conv_to_data.find(conv)!=conv_to_data.end())
			{
				conv=get_true_random_number_nz();
			}
			return conv;
		}
		int is_conv_used(u32_t conv)
		{
			return conv_to_data.find(conv)!=conv_to_data.end();
		}
		int is_data_used(T data)
		{
			return data_to_conv.find(data)!=data_to_conv.end();
		}
		u32_t find_conv_by_data(T data)
		{
			return data_to_conv[data];
		}
		T find_data_by_conv(u32_t conv)
		{
			return conv_to_data[conv];
		}
		int update_active_time(u32_t conv)
		{
			//return conv_last_active_time[conv]=get_current_time();
			lru.update(conv);
			return 0;
		}
		int insert_conv(u32_t conv,T data)
		{
			data_to_conv[data]=conv;
			conv_to_data[conv]=data;
			//conv_last_active_time[conv]=get_current_time();
			lru.new_key(conv);
			return 0;
		}
		int erase_conv(u32_t conv)
		{
			if(disable_conv_clear) return 0;
			T data=conv_to_data[conv];
			if(additional_clear_function!=0)
			{
				additional_clear_function(data);
			}
			conv_to_data.erase(conv);
			data_to_conv.erase(data);
			//conv_last_active_time.erase(conv);
			lru.erase(conv);
			return 0;
		}
		int clear_inactive(char * info=0)
		{
			if(get_current_time()-last_clear_time>conv_clear_interval)
			{
				last_clear_time=get_current_time();
				return clear_inactive0(info);
			}
			return 0;
		}
		int clear_inactive0(char * info)
		{
			if(disable_conv_clear) return 0;


			unordered_map<u32_t,u64_t>::iterator it;
			unordered_map<u32_t,u64_t>::iterator old_it;

			//map<uint32_t,uint64_t>::iterator it;
			int cnt=0;
			//it=clear_it;
			int size=lru.size();
			int num_to_clean=size/conv_clear_ratio+conv_clear_min;   //clear 1/10 each time,to avoid latency glitch

			num_to_clean=min(num_to_clean,size);

			my_time_t current_time=get_current_time();
			for(;;)
			{
				if(cnt>=num_to_clean) break;
				if(lru.empty()) break;

				u32_t conv;
				my_time_t ts=lru.peek_back(conv);

				if(current_time- ts < conv_timeout) break;

				erase_conv(conv);
				if(info==0)
				{
					mylog(log_info,"conv %x cleared\n",conv);
				}
				else
				{
					mylog(log_info,"[%s]conv %x cleared\n",info,conv);
				}
				cnt++;
			}
			return 0;
		}


		/*
	conv_manager_t();
	~conv_manager_t();
	int get_size();
	void reserve();
	void clear();
	u32_t get_new_conv();
	int is_conv_used(u32_t conv);
	int is_u64_used(T u64);
	u32_t find_conv_by_u64(T u64);
	T find_u64_by_conv(u32_t conv);
	int update_active_time(u32_t conv);
	int insert_conv(u32_t conv,T u64);
	int erase_conv(u32_t conv);
	int clear_inactive(char * ip_port=0);
	int clear_inactive0(char * ip_port);*/
};//g_conv_manager;

struct blob_t:not_copy_able_t //used in conn_info_t.
{
	union  tmp_union_t//conv_manager_t is here to avoid copying when a connection is recovered
	{
		conv_manager_t<address_t> c;
		conv_manager_t<u64_t> s;
		//avoid templates here and there, avoid pointer and type cast
		tmp_union_t()
		{
			if(program_mode==client_mode)
			{
				new( &c ) conv_manager_t<address_t>();
			}
			else
			{
				assert(program_mode==server_mode);
				new( &s ) conv_manager_t<u64_t>();
			}
		}
		~tmp_union_t()
		{
			if(program_mode==client_mode)
			{
				c.~conv_manager_t<address_t>();
			}
			else
			{
				assert(program_mode==server_mode);
				s.~conv_manager_t<u64_t>();
			}
		}
	}conv_manager;

	anti_replay_t anti_replay;//anti_replay_t is here bc its huge,its allocation is delayed.
};
struct conn_info_t     //stores info for a raw connection.for client ,there is only one connection,for server there can be thousand of connection since server can
//handle multiple clients
{
	current_state_t state;

	raw_info_t raw_info;
	u64_t last_state_time;
	u64_t last_hb_sent_time;  //client re-use this for retry
	u64_t last_hb_recv_time;
	//long long last_resent_time;

	my_id_t my_id;
	my_id_t oppsite_id;


	fd64_t timer_fd64;
	fd64_t udp_fd64;

	my_id_t oppsite_const_id;

	blob_t *blob;

	uint8_t my_roller;
	uint8_t oppsite_roller;
	u64_t last_oppsite_roller_time;

//	ip_port_t ip_port;

/*
	const uint32_t &ip=raw_info.recv_info.src_ip;
	const uint16_t &port=raw_info.recv_info.src_port;

*/
	 void recover(const conn_info_t &conn_info);
	void re_init();
	conn_info_t();
	void prepare();
	conn_info_t(const conn_info_t&b);
	conn_info_t& operator=(const conn_info_t& b);
	~conn_info_t();
};//g_conn_info;

struct conn_manager_t  //manager for connections. for client,we dont need conn_manager since there is only one connection.for server we use one conn_manager for all connections
{

 u32_t ready_num;

 //unordered_map<int,conn_info_t *> udp_fd_mp;  //a bit dirty to used pointer,but can void unordered_map search
 //unordered_map<int,conn_info_t *> timer_fd_mp;//we can use pointer here since unordered_map.rehash() uses shallow copy

 unordered_map<my_id_t,conn_info_t *> const_id_mp;

 unordered_map<address_t,conn_info_t*> mp; //put it at end so that it de-consturcts first

 //lru_collector_t<address_t> lru;

 unordered_map<address_t,conn_info_t*>::iterator clear_it;

 long long last_clear_time;

 conn_manager_t();
 int exist(address_t addr);
 /*
 int insert(uint32_t ip,uint16_t port)
 {
	 uint64_t u64=0;
	 u64=ip;
	 u64<<=32u;
	 u64|=port;
	 mp[u64];
	 return 0;
 }*/
 conn_info_t *& find_insert_p(address_t addr);  //be aware,the adress may change after rehash //not true?
 conn_info_t & find_insert(address_t addr) ; //be aware,the adress may change after rehash

 int erase(unordered_map<address_t,conn_info_t*>::iterator erase_it);
int clear_inactive();
int clear_inactive0();

};

extern conn_manager_t conn_manager;

void server_clear_function(u64_t u64);

int send_bare(raw_info_t &raw_info,const char* data,int len);//send function with encryption but no anti replay,this is used when client and server verifys each other
//you have to design the protocol carefully, so that you wont be affect by relay attack
//int reserved_parse_bare(const char *input,int input_len,char* & data,int & len); // a sub function used in recv_bare
int recv_bare(raw_info_t &raw_info,char* & data,int & len);//recv function with encryption but no anti replay,this is used when client and server verifys each other
//you have to design the protocol carefully, so that you wont be affect by relay attack
int send_handshake(raw_info_t &raw_info,my_id_t id1,my_id_t id2,my_id_t id3);// a warp for send_bare for sending handshake(this is not tcp handshake) easily
int send_safer(conn_info_t &conn_info,char type,const char* data,int len);  //safer transfer function with anti-replay,when mutually verification is done.
int send_data_safer(conn_info_t &conn_info,const char* data,int len,u32_t conv_num);//a wrap for  send_safer for transfer data.
//int reserved_parse_safer(conn_info_t &conn_info,const char * input,int input_len,char &type,char* &data,int &len);//subfunction for recv_safer,allow overlap

//int recv_safer(conn_info_t &conn_info,char &type,char* &data,int &len);///safer transfer function with anti-replay,when mutually verification is done.

int recv_safer_multi(conn_info_t &conn_info,vector<char> &type_arr,vector<string> &data_arr);//new api for handle gro
#endif /* CONNECTION_H_ */
